1. Technical Field
Embodiments of the present invention relate to a sheet feeder such as a manual sheet feeder and an image forming apparatus that includes the sheet feeder.
2. Related Art
Image forming apparatuses generally include a manual sheet feeder that feeds a recording medium from outside the apparatus. Equipping the manual sheet feeder, the image forming apparatus can produce copies on special sheets such as OHP (overhead projector) films or perform interrupt copy processing.
The manual sheet feeder of the image forming apparatus typically includes a bypass tray that is openably closed with respect to a manual sheet feeding port located on a side surface of the image forming apparatus. The bypass tray is generally closed to become a part of the outer surface of the image forming apparatus. In a manual feeding operation, a user opens the bypass tray with a given angle with respect to the side surface of the image forming apparatus. Examples of the configuration are disclosed in Japanese Patent Application Publication Nos. JP 2008-094528-A, JP 2007-050972-A (JP 4764676-B), and JP 2009-167005.
However, JP 2008-094528-A discloses the configuration in which a bypass tray is openably closed to cover the manual feeding port to minimize the entire height of the image forming apparatus. Therefore, it is difficult to reduce the size of the bypass tray by the height of a side guide. Consequently, the configuration is believed not to appropriate for space saving.
The side guide is a paper guide to align a paper width that is a position in a direction perpendicular to a sheet feeding direction of a sheet or sheets loaded on the bypass tray. The side guide prevents zigzag and skew of the sheet(s) in the sheet feeding. Therefore, the side is generally formed to be higher than the maximum possible thickness of a sheet stack that can be loaded on the bypass tray. That is, the number of sheets that can be loaded on the bypass tray at one time is limited by the height of the side guide.
By contrast, JP 2007-050972-A discloses the configuration in which an outer surface of the bypass tray is stored as a substantially same surface as an outer surface of the duplex unit, and the bypass tray opens and closes the bypass tray via a link mechanism so that a sheet loading surface of the bypass tray, which is an inner surface of the bypass tray, is connected to the manual sheet feeding port in the copying operation. Consequently, even if the configuration is applicable to space saving, the bypass tray is stored in the side surface of the duplex unit while moving the bypass tray in the vertical direction. Therefore, in a case in which the height of the side fence disclosed in JP 2007-050972-A, which corresponds to the side fence disclosed in JP 2008-094528-A, is secured, the size of the duplex unit increases.
Further, JP2009-167005 discloses a configuration that can reduce the installation space. However, a sufficient space is required to provide an auxiliary fence (auxiliary fences) immediately before a registration roller pair disposed at a downward side in a sheet conveying direction. Therefore, if the space is not secured, it tends to be difficult to locate the auxiliary fence(s) due to the layout restrictions.